What attracts people to Islam?
The poor are attracted to Islam because of its 'zakat'.
This is where 2.5% of all assets are redistributed to the needy.
This was a huge difference compared to the aristocratic pre-Muhummad Mecca, but is still applicable today.
The religious were attracted to the absolute "monotheism" of Islam, and the Koran's strict commands seemed straight forward enough - providing a much needed law structure.
At least in America, Muslims convert by playing on the class structures and social structures in society. Specifically, the Nation of Islam converts in the prisons, where many African-Americans find purpose.
The Nation of Islam believes that there is a white and Christian conspiracy to keep down all blacks, which is ridiculous. It advocates racism and intolerance.
The Nation of Islam portrays Africans as a blessed people; but they are in every religion, just like every other man and woman of any background.
The main reason for conversion is ignorance of one's own religion, ignorance of Islam, disillusionment with society (which is no reason to leave a religion, especially one that teaches the meek will inherit the earth), and false truth.